Controversy is ongoing regarding the relationship between ore formation and the structural evolution of the Hadamengou gold deposit.To address this issue,we conducted a comprehensive investigation of mineralization-re...Controversy is ongoing regarding the relationship between ore formation and the structural evolution of the Hadamengou gold deposit.To address this issue,we conducted a comprehensive investigation of mineralization-related structures,geochronology and Fe isotopes.From the perspective of spatial evolution,hydrothermal fluids originating from the Shadegai and Xishadegai plutons have extracted accumulated ore-forming elements from the Wulashan Group(Ar2WL)and then evolved,initiating at Exploration Line 11 and migrating eastwards and westwards along the EW-trending thrust fault system to form orebodies.From the temporal evolution standpoint,the Wulashan Group(Ar_(2)WL)experienced diagenesis(2591.00 Ma to 2204.00 Ma)and metamorphism(2074.00 Ma to 1625.00 Ma)from late Neoarchean to early Paleoproterozoic,when ore-forming materials were initially accumulated;in the early Paleozoic(440.71 Ma to 425.00 Ma),the collision led to the formation of early-stage EW-trending imbricated thrust faults,which established a fundamental structural framework for the orefield and further accumulated ore-forming materials;from the late Paleozoic to the Mesozoic,multiple subsequent episodes of regional tectonic-magmatic-hydrothermal events have superimposed,modified and reactivated the thrust fault system.Notably,the Triassic period,particularly between 245.00 Ma and 217.90 Ma,is considered to be a primary ore-forming stage.In summary,the intricate relationship between ore-formation and structural evolution has been fundamentally elucidated.展开更多
Based on comprehensive petrological, geochronological, and geochemical studies, this study analyzed the relationships between the Beiya gold-polymetallic skarn deposit and quartz syenite porphyries, and discussed the ...Based on comprehensive petrological, geochronological, and geochemical studies, this study analyzed the relationships between the Beiya gold-polymetallic skarn deposit and quartz syenite porphyries, and discussed the source（s） and evolution of magmas. Our results suggest that syenite porphyries（i.e. the Wandongshan, the Dashadi, and the Hongnitang porphyries）, which formed between the Eocene and the early Oligocene epochs, are the sources for the gold-polymetallic ores at the Beiya deposit. Carbonate rocks（T2 b） of the Triassic Beiya Formation in the ore district provide favorable host space for deposit formation. Fold and fault structures collectively play an important role in ore formation. The contact zone between the porphyries and carbonates, the structurally fractured zone of carbonate and clastic rocks, and the zone with well-developed fractures are the ideal locations for ore bodies. Four types of mineralization have been recognized： 1） porphyry-style stockwork gold–iron（copper） ore, 2） skarn-style gold-iron（copper and lead） ore in the near contact zone, 3） strata-bound, lense-type lead–silver–gold ore in the outer contact zone, and 4） distal vein-type gold–lead–silver ore. Supergene processes led to the formation of oxide ore, such as the weathered and accumulated gold–iron ore, the strata-bound fracture oxide ore, and the structure-controlled vein-type ore. Most of these ore deposits are distributed along the axis of the depressed basin, with the hypogene ore controlling the shape and characteristics of the oxide ore. This study provides critical geology understanding for mineral prospecting scenarios.展开更多
To address the issues for assessing and prospecting the replaceable resource of crisis mines, a geological ore-controlling field model and a mineralization distribution field model were proposed from the viewpoint of ...To address the issues for assessing and prospecting the replaceable resource of crisis mines, a geological ore-controlling field model and a mineralization distribution field model were proposed from the viewpoint of field analysis. By dint of solving the field models through transferring the continuous models into the discrete ones, the relationship between the geological ore-controlling effect field and the mineralization distribution field was analyzed, and the quantitative and located parameters were extracted for describing the geological factors controlling mineralization enrichment. The method was applied to the 3-dimensional localization and quantitative prediction for concealed ore bodies in the depths and margins of the Daehang mine in Guangxi, China, and the 3-dimensional distribution models of mineralization indexes and ore-controlling factors such as magmatic rocks, strata, faults, lithology and folds were built. With the methods of statistical analysis and the non-linear programming, the quantitative index set of the geological ore-controlling factors was obtained. In addition, the stereoscopic located and quantitative prediction models were set up by exploring the relationship between the mineralization indexes and the geological ore-controlling factors. So far, some concealed ore bodies with the resource volume of a medium-sized mineral deposit are found in the deep parts of the Dachang Mine by means of the deep prospecting drills following the prediction results, from which the effectiveness of the predication models and results is proved.展开更多
The Baoshan Cu-Pb-Zn polymetallic deposit is lied in the central Nanling mineralization zone,and belongs to the junction area of the Chenzhou-Linwu fault zone and the Leiyang-Linwu fault zone.It is a significant part ...The Baoshan Cu-Pb-Zn polymetallic deposit is lied in the central Nanling mineralization zone,and belongs to the junction area of the Chenzhou-Linwu fault zone and the Leiyang-Linwu fault zone.It is a significant part of Nanling polymetallic deposit belt.The outcropping stratas consist of upper Devonian Shetianqiao,Xikuangshan Formation,Lower Carboniferous Menggong’ao,Shidengzi,Ceshui,and Zimenqiao Formation.Igneous rocks in the Baoshan ore area mainly comprise granodiorite porphyry.Furthermore,the radio isotopic age ranges from 123 Ma to 183 Ma,belonging to the early to middle Yanshanian.展开更多
Abstract Low-angle faults include those occurring in thrust-nappe structures in a compressive setting and the detachment of metamorphic core complexes in an extensional setting. All low-angle faults have their own par...Abstract Low-angle faults include those occurring in thrust-nappe structures in a compressive setting and the detachment of metamorphic core complexes in an extensional setting. All low-angle faults have their own particularities. The low-angle fault plays an important role in controlling over some endogenetic metallic ore deposits. Based on studies of the Xiaoban gold deposit, Xinzhou gold deposit, and Longfengchang polymetallic ore deposit, and comparisons with other mines, the authors conclude the ore-controlling implications of low-angle faults as follows. (1) Because of high temperature and high pressure, as well as strong ductile deformation, the internal energy of the elements rises in the large-scale deep ductile low-angle faults, which causes the elements to activate and differentiate from the source rocks, forming ore-bearing hydrothermal solution, and bring mineralization to happen. (2) When rising from depths and flowing along the low-angle faults, the ore-bearing hydrothermal solution will alter and replace the tectonites in the fault zone. The rocks of the hanging side and the heading side differ in lithology, texture and structure, which results in changes or dissimilarities of the physical-chemical conditions. This destroys the balance of the hydrothermal solution system and causes the dissolved ore-forming elements to precipitate; as a result, a deposit is formed. Therefore, the meso-shallow ductile-brittle low-angle faults play the role of a geochemical interface in the process of mineralization. (3) Low-angle faults are often one of the important host structures.展开更多
The Qifengcha-Detiangou gold deposit is a medium-sized deposit recently found in Huairou County, Beijing. It belongs to the altered mylonite type with superimposed quartz vein type and is related to the early Yanshani...The Qifengcha-Detiangou gold deposit is a medium-sized deposit recently found in Huairou County, Beijing. It belongs to the altered mylonite type with superimposed quartz vein type and is related to the early Yanshanian magmatic activity. Characterized by multiperiodic activity, the NE-trending Qifengcha fault is a regional ore-controlling structure in the area, and gold mineralization develops only in its southeastern part. Meanwhile, gold mineralization is controlled by the Yunmengshan metamorphic core complex. The nearly N-S- and E-W-trending low-angle detachment faults, reformed by the Qifengcha fault in the northwestern part of the core complex, are the main ore-bearing faults. All discovered gold deposits are located within an area 1.5–4.0 km away from the boundary of the upwelling centre. The N-S- (NNE-) and E-W-trending ore-bearing faults are ductile-brittle structural zones developing in shallow positions and subjected mainly to compressive deformation. The structural ore-controlling effects are as follows. (1) The attitude, shape, and distribution of gold orebodies are controlled by faults. (2) There is a negative correlation between the gold abundance and the magnetic anisotropy (P) of the altered mylonite samples from the deposit, which shows that the gold mineralization is later than the structural deformation. (3) Quartz vein type mineralization is superimposed on altered mylonite type mineralization. (4) In mineralized mylonite, the stronger the ductile shear deformation, the easier the late-stage gold mineralization to occur and the higher the gold abundance. The richest gold mineralization occurs only around the centre of the fault subjected to the strongest deformation.展开更多
The Ailao Mountain is one of the most important metallogenic belts ofpolymetallic deposits in the Sanjiang region, southwestern China. Located in the southern segment of this metallogenic belt, the newly-discovered Ch...The Ailao Mountain is one of the most important metallogenic belts ofpolymetallic deposits in the Sanjiang region, southwestern China. Located in the southern segment of this metallogenic belt, the newly-discovered Chang＇an gold deposit is large in scale （Fig. 1A）, and has attracted much attention among geologists. The ore-hosted rocks in the district include the Late Ordovician Xiangyang Fm. sandstone and clastic rocks and the Early Silurian Kanglang Fm. dolomite. Affected by the multistage tectonic activities, stocks and dykes of lamprophyre, dolerite, syenite porphyry and orthoclasite are widely exposed, and the orebodies are in symbiosis with or crosscut the dyke rocks.展开更多
1 Introduction The Lehonglead-zincdeposit is a large-sized Pb-Zn depositnewly found in recent years in the Sichuan-Yunnan-Guizhou Lead-zinc Poly-metallic Mineralization Area,which occurrenceis strictly
Based on quantitative and semi-quantitative mathematical and mechanical analysis of the shape, motion, structural factors, stress field and deformation field of the ore-hosting faults in the Xincheng-Hexi gold deposit...Based on quantitative and semi-quantitative mathematical and mechanical analysis of the shape, motion, structural factors, stress field and deformation field of the ore-hosting faults in the Xincheng-Hexi gold deposit, the ore-controlling features of faults and mineralization mechanism are discussed. It is concluded that the mineralization is controlled by the main faults, subsidiary fractures, joint density, mechanical features and deformation of the faults. The ore bodies are mainly located in the lower part of the convex crest and upper part of the concave trough of the main undulating fault surface. Mineralization is positively correlated to the development of subsidiary fractures and joints, which correspond to zones of low internal stress and high body strain and shear strain. They are favourable positions for mineralization and alteration.展开更多
1 Introduction The Dongshengmiao deposit is a super-large Zn-Pb polymetallic sulfide deposit which occurring in the Langshan-Zhaertaaishan metallogenic belt,and located in the western margin of the North China Platfor...1 Introduction The Dongshengmiao deposit is a super-large Zn-Pb polymetallic sulfide deposit which occurring in the Langshan-Zhaertaaishan metallogenic belt,and located in the western margin of the North China Platform.The ore-bodies of Dongshengmiao deposits are mainly hosted in the second Formation of Langshan Group.There are some studies on the geological characteristics(Peng et al.,2004),geological and展开更多
1 Introduction The huize Zn-Pb ore district in Yunnan province is locatedinthecentralsouthernofthe Sichuan—Yunnan—GuizhouPb-ZnPoly-metallic Mineralization Area in the southwestern margin of the Yangtze Block,and is ...1 Introduction The huize Zn-Pb ore district in Yunnan province is locatedinthecentralsouthernofthe Sichuan—Yunnan—GuizhouPb-ZnPoly-metallic Mineralization Area in the southwestern margin of the Yangtze Block,and is strictly controlled by fault structures.It has developed to one of the famous production bases of lead&zinc and germanium in China.展开更多
In recent2 0 years,because of the finding ofmany large- superlargegold deposits,we re- new the theories for prospecting and gain many things and conceptions.The current geo- chemical and gold- forming theories underli...In recent2 0 years,because of the finding ofmany large- superlargegold deposits,we re- new the theories for prospecting and gain many things and conceptions.The current geo- chemical and gold- forming theories underline the importance of the early submarine volcano- sedimentation,metamorphic differention,sedimentation of terrigenous clastics,thermal spring and it’s sedimentation,syngenesis process and other hypergene supplying the source for metallogenic materials.According to the study for source bed(rock) and depsitional for- mation of gold,we find that gold will be gradually enriched and mineralized in source bed (rock) ,because of variousgeologicprocesses,such as regional metamorphism ormigmatiza- tion,geothermal bittern,volcanism. The ore- control of deep and giant fault and ductile shear beltand tectono- flash space is emphasized,especially,we should notice the long- term, succession and multistage of the展开更多
Polymetallic nodules,hereinafter referred to as PN,enriched with Co,Ni,Mn,and Cu,are likely to be commercially mined in the near future.These metals in PN are potential strategic alternatives for the world’s energy t...Polymetallic nodules,hereinafter referred to as PN,enriched with Co,Ni,Mn,and Cu,are likely to be commercially mined in the near future.These metals in PN are potential strategic alternatives for the world’s energy transition.Therefore,intensive studies are necessary on the spatial distribution patterns of PN in the deep sea.In this study,the distribution probabilities of PN in the Pacific,Indian and Atlantic oceans were estimated based on binary logistic regression of PN occurrence with ore-controlling factors including water depth(WD),marine sediment thickness(SedTh),Calcium carbonate(CaCO_(3))concentrations in surface sediments,primary productivity(PP),near bottom current velocities(BC).Furthermore,the distribution probability of PN was constrained by seafloor ages and PN sites,and subsequently,the prospects for nodules in the Pacific,Indian and Atlantic oceans were obtained.The results indicate that the low-latitude Pacific region(30°N-30°S),particularly the Clarion-Clipperton Zone and the Penrhyn Basin,is the most promising area for PN exploration.展开更多
The Cretaceous gold deposits along the margins of the North China Craton(NCC),which formed in a craton destruction setting,display geological characteristics similar to traditional orogenic gold deposits typically ass...The Cretaceous gold deposits along the margins of the North China Craton(NCC),which formed in a craton destruction setting,display geological characteristics similar to traditional orogenic gold deposits typically associated with accretionary orogeny.These deposits,known as Jiaodong-type gold deposits,have attracted considerable attention.However,the lithospheric controls and formation mechanisms of these deposits remain unclear,as they cannot be fully explained by the supracrustal metamorphic genetic model commonly applied to classic orogenic gold deposits.In this study,the compiled S-Hg-Pb isotope ratios of gold deposits on different NCC margins display compatible variations to the Sr-Nd-Hg isotope ratios of mafic dikes spatial-temporally associated with the deposits.This implies that mantle lithosphere,metasomatized by variable proportions of oceanic and continental crust,was the source for both gold deposits and mafic dikes.Increase of oxygen fugacity and zirconεHf(t)from pre-to syn-gold granites suggests continuous basic magma underplating,which could induce concentrations of Au-rich sulfides and contribute additional Au to auriferous CO_(2)-rich fluids derived from metasomatized mantle lithosphere and basic magma.Localization of gold deposits was controlled by craton-margin sinistral shearing induced by clockwise rotation of the craton coincident with distal emplacement of metamorphic core complexes.Thus,the Cretaceous Jiaodong-type orogenic gold deposits were derived from fertilized mantle lithosphere through such crust-mantle processes within a lithosphere thinning background.展开更多
Gold deposits in Jiaodong,termed Jiaodong-type,are tectonically located in the southeastern margin of the North China Craton.Their major features are reviewed in this paper to highlight the differences between Jiaodon...Gold deposits in Jiaodong,termed Jiaodong-type,are tectonically located in the southeastern margin of the North China Craton.Their major features are reviewed in this paper to highlight the differences between Jiaodong deposits and other genetic types of gold deposits.The mineralization was synchronized with asthenosphere upwelling indicated by synore OIB-like mafic dike and large-scale crustal thinning suggested by decrease of Sr/Y from pre-ore to syn-ore granites.Asthenosphere upwelling induced by the roll-back of Paleo-Pacific Plate drove partial melting of lithospheric mantle and devolatilization,which induced the release of the ore-forming fluids.In concomitant with magmatic records,mineralization migrated from the western Jiaobei terrane(133–127 Ma)to the eastern Sulu orogenic belt(114–108 Ma),corresponding to the eastward roll-back of Paleo-Pacific Plate.Gold mineralization in Jiaodong formed in the transitions of ductile to brittle deformation,rapid to slow crustal uplift,and regional compression to extension.In the regional-scale,the gold deposits in the Jiaobei terrane are mostly situated at intersections between NE-trending faults and EW-trending basement faults,and gold orebodies dominantly controlled by the lithologic contacts between Precambrian metamorphic rocks and Mesozoic granites.The mineralization was dominated by the disseminated-veinlet ores related to quartz–sericite alteration in strong cataclasite-breccia zone,with subsidiary thick quartz-sulfide veins developed in secondary fault zones.The ore-forming fluids belong to a H_(2)O–CO_(2)–NaCl±CH_(4)system and show minor variations in salinity among different types of ore.Structure-fluid feedback involving fluid-rock reaction and hydrofracturing triggered the fluid phase separation and resultant gold deposition.The Jiaodong gold deposits are distinct from orogenic and intrusion-related gold deposits in terms of tectonic setting,origin of ore-forming fluids,and mechanism of gold deposition.展开更多
The northwest of Jiaodong peninsula is characterized by its greatest gold concentration area, enormous gold reserves and limited time interval （115±5Ma） of gold mineralization in China. Studies show that the ea...The northwest of Jiaodong peninsula is characterized by its greatest gold concentration area, enormous gold reserves and limited time interval （115±5Ma） of gold mineralization in China. Studies show that the east area of north China began its mantle plume evolution since the Yanshanian movement, and the Laiyang sub-mantle plume and its surrounding mantle branches such as those in Guojiadian, Aishan and Panshidian were formed in the mineralization concentration area of northwestern Jiaodong peninsula. With the development of mantle plume →sub-mantle plume → mantle branch→ favorable expending structures, the deep-derived hydrothermal fluid moved up to the favorable places, such as brittle-ductile or ductile-brittle shearing zones, the internal and external contact zones of intrusions, dense fracturing zones and the contact zones between dikes and countryrocks, and concentrated into deposits. Then the gold mineralization concentration zones that are centralized on mantle branches were formed. This study takes Guojiadian mantle branch as an example to discuss their metallogenetism and conclude the metallogenetic mode.展开更多
Structural network studies could give appropriate opportunities to understanding structural/hydrothermal events,transportation of ore-forming fluids and water/rock interaction process.Four structural deformation/hydro...Structural network studies could give appropriate opportunities to understanding structural/hydrothermal events,transportation of ore-forming fluids and water/rock interaction process.Four structural deformation/hydrothermal events have been identified in the Jiaojia fault zone according to microtexture and deformation of quartz and feldspars.Plagioclase experienced ductile deformation period with bended polysynthetic twin stripes(>450℃)in the early stage,followed by K-feldspar alteration period with ductile-brittle deformation and subgrain rotation recrystallization of quartz(380-450℃).Then,sericitization period occurred extensive ductile-brittle deformation(350-420℃)and extensive subgrain rotation recrystallization with a little bulging recrystallization in quartz.In the last,gold precipitation-related pyrite-sericite-quartz alteration was dominated by brittle deformation(300-380℃)and total bulging recrystallization of quartz.From the K-feldspar alteration zone and sericitization zone to pyrite-sericitequartz alteration zone,fractal dimension values of dynamically recrystallized quartz grains increase from 1.07 and 1.24 to 1.32,the calculated paleo strain rate values of dynamically recrystallized quartz range from 10^-10^.7(380℃)-10^-9.6(450℃)and 10^-9.3(350℃)-10^-8.2(420℃)to 10^-9.5(300℃)-10^-8.0(380℃),and the paleo differential stress values increase from 36.9 and 39.3,to 121.3 MPa.The increase of fractal dimension values and decrease of grain size from pyrite-sericite-quartz alteration zone and sericitization zone to K-feldspar alteration zone decreased average water/rock ratio values,which could lead to different acidity and redox conditions of ore-forming fluids and mineralization differences.Two kinds of orecontrolling fractures have been distinguished which include the gentle dip types(18°-50°)with NW(315°-355°)and SW(180°-235°)dip hosting No.Ⅰorebodies and the steep dip types(74°-90°)with NE(45°-85°)and SE(95°-165°)dip hosting No.Ⅲorebodies.These faults/fractures crosscut altered Linglong granite of footwall of the Jiaojia fault zone as rhombohedrons that promoted the connection between fractures in the K-feldspar alteration zone and fluid flow passages near the main fault face.Research results indicate No.Ⅰand No.Ⅲorebodies should be derived from the same mineralization event and belong to different orebody types in different mineralization sites under the same structural networks.展开更多
The Pengshan Sn-Pb-Zn polymetallic orefield is located in the Jiujiang-Ruichang region, which is a segment of the middle-lower Yangtze River metallogenic belt. The Pengshan late Yanshanian buried pluton with granitic ...The Pengshan Sn-Pb-Zn polymetallic orefield is located in the Jiujiang-Ruichang region, which is a segment of the middle-lower Yangtze River metallogenic belt. The Pengshan late Yanshanian buried pluton with granitic composition is a calc-alkaline pluton, intrusion of which is responsible for the formation of the Sn-Pb-Zn polymetallic deposit through providing thermodynamic condition and ore-forming material. The long-active basement rifts initially formed in the Jinning period and the domal structure with induced secondary order faults formed by emplacement of the pluton, such as ring-detachment fault, top-detachment fault and joint fissure, act as the passage-way for magma and ore-forming fluid and impounding structure for ore deposit. The magma to form the pluton with DI>90 is intensively differentiated. The variation of the ore-forming fluid in composition with falling in temperature caused by action of magmatic hydrothermal convection system combined with groundwater convection system attributes to mineralization of various types in the orefield. The mineralization process can be divided into six stages, i.e., greisenization, skarnization of early stage, fluorite-stanniferous silication stage, skarnization of advanced stage, quartz and cassiterite-sulfuration stage and carbonation stage. The mineral assemblages formed in different mineralization stages are different owing to temperature changing and may be overlapped in space. Malayaite is recognized from the mineral assemblage formed in the fluorite-stanniferous silication stage. The ores in the Pengshan Sn-Pb-Zn polymetallic deposit are spatially zoned with variation from As-Sn mineral assemblage of high temperature in the inner zone through Sn-Pb and Pb-Zn-Ag mineral assemblage of middle temperature in the middle zone to fluorite mineral assemblage of low temperature in the outer zone. The exchanging of Sn, Mg and Fe between biotite and hydrothermal fluid resulted from variation of physicochemical condition during evolution processes of the hydrothermal fluid and its role in mineralization are also discussed in this paper.展开更多
基金the financial support by the Major Research Plan of National Natural Science Foundation of China(92062219)the Young Elite Scientists Sponsorship Program by BAST(No.BYESS2023411)+2 种基金the Open Research Project from the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(GPMR202407)the Geological Survey Project of the China Geological Survey„General survey of Hadamengou Rock Gold Deposit in Inner Mongolia'(DD20191017)the Geological Survey Project(H90063).
文摘Controversy is ongoing regarding the relationship between ore formation and the structural evolution of the Hadamengou gold deposit.To address this issue,we conducted a comprehensive investigation of mineralization-related structures,geochronology and Fe isotopes.From the perspective of spatial evolution,hydrothermal fluids originating from the Shadegai and Xishadegai plutons have extracted accumulated ore-forming elements from the Wulashan Group(Ar2WL)and then evolved,initiating at Exploration Line 11 and migrating eastwards and westwards along the EW-trending thrust fault system to form orebodies.From the temporal evolution standpoint,the Wulashan Group(Ar_(2)WL)experienced diagenesis(2591.00 Ma to 2204.00 Ma)and metamorphism(2074.00 Ma to 1625.00 Ma)from late Neoarchean to early Paleoproterozoic,when ore-forming materials were initially accumulated;in the early Paleozoic(440.71 Ma to 425.00 Ma),the collision led to the formation of early-stage EW-trending imbricated thrust faults,which established a fundamental structural framework for the orefield and further accumulated ore-forming materials;from the late Paleozoic to the Mesozoic,multiple subsequent episodes of regional tectonic-magmatic-hydrothermal events have superimposed,modified and reactivated the thrust fault system.Notably,the Triassic period,particularly between 245.00 Ma and 217.90 Ma,is considered to be a primary ore-forming stage.In summary,the intricate relationship between ore-formation and structural evolution has been fundamentally elucidated.
基金jointly financially supported by “Yunling Scholars” Research Project from Yunnan Province,China Geological Survey Project(No.DD20160124 and 12120114013501)the National Natural Science Foundation of China(grant No.41602103)the “Study on metallogenic regularities and metallogenic series of gold-polymetallic deposits,Northwestern Yunnan Province” research project(E1107)from Yunnan Gold&Mining Group Co.,Ltd
文摘Based on comprehensive petrological, geochronological, and geochemical studies, this study analyzed the relationships between the Beiya gold-polymetallic skarn deposit and quartz syenite porphyries, and discussed the source（s） and evolution of magmas. Our results suggest that syenite porphyries（i.e. the Wandongshan, the Dashadi, and the Hongnitang porphyries）, which formed between the Eocene and the early Oligocene epochs, are the sources for the gold-polymetallic ores at the Beiya deposit. Carbonate rocks（T2 b） of the Triassic Beiya Formation in the ore district provide favorable host space for deposit formation. Fold and fault structures collectively play an important role in ore formation. The contact zone between the porphyries and carbonates, the structurally fractured zone of carbonate and clastic rocks, and the zone with well-developed fractures are the ideal locations for ore bodies. Four types of mineralization have been recognized： 1） porphyry-style stockwork gold–iron（copper） ore, 2） skarn-style gold-iron（copper and lead） ore in the near contact zone, 3） strata-bound, lense-type lead–silver–gold ore in the outer contact zone, and 4） distal vein-type gold–lead–silver ore. Supergene processes led to the formation of oxide ore, such as the weathered and accumulated gold–iron ore, the strata-bound fracture oxide ore, and the structure-controlled vein-type ore. Most of these ore deposits are distributed along the axis of the depressed basin, with the hypogene ore controlling the shape and characteristics of the oxide ore. This study provides critical geology understanding for mineral prospecting scenarios.
基金Project(2007CB416608) supported by the National Basic Research Program of ChinaProject(2006BAB01B07) supported by the National Science and Technology Pillar Program during the 11th Five-Year Plan Period
文摘To address the issues for assessing and prospecting the replaceable resource of crisis mines, a geological ore-controlling field model and a mineralization distribution field model were proposed from the viewpoint of field analysis. By dint of solving the field models through transferring the continuous models into the discrete ones, the relationship between the geological ore-controlling effect field and the mineralization distribution field was analyzed, and the quantitative and located parameters were extracted for describing the geological factors controlling mineralization enrichment. The method was applied to the 3-dimensional localization and quantitative prediction for concealed ore bodies in the depths and margins of the Daehang mine in Guangxi, China, and the 3-dimensional distribution models of mineralization indexes and ore-controlling factors such as magmatic rocks, strata, faults, lithology and folds were built. With the methods of statistical analysis and the non-linear programming, the quantitative index set of the geological ore-controlling factors was obtained. In addition, the stereoscopic located and quantitative prediction models were set up by exploring the relationship between the mineralization indexes and the geological ore-controlling factors. So far, some concealed ore bodies with the resource volume of a medium-sized mineral deposit are found in the deep parts of the Dachang Mine by means of the deep prospecting drills following the prediction results, from which the effectiveness of the predication models and results is proved.
基金Supported by the Program of Superseding Resources Prospecting in Crisis Mines in China(20089927)
文摘The Baoshan Cu-Pb-Zn polymetallic deposit is lied in the central Nanling mineralization zone,and belongs to the junction area of the Chenzhou-Linwu fault zone and the Leiyang-Linwu fault zone.It is a significant part of Nanling polymetallic deposit belt.The outcropping stratas consist of upper Devonian Shetianqiao,Xikuangshan Formation,Lower Carboniferous Menggong’ao,Shidengzi,Ceshui,and Zimenqiao Formation.Igneous rocks in the Baoshan ore area mainly comprise granodiorite porphyry.Furthermore,the radio isotopic age ranges from 123 Ma to 183 Ma,belonging to the early to middle Yanshanian.
文摘Abstract Low-angle faults include those occurring in thrust-nappe structures in a compressive setting and the detachment of metamorphic core complexes in an extensional setting. All low-angle faults have their own particularities. The low-angle fault plays an important role in controlling over some endogenetic metallic ore deposits. Based on studies of the Xiaoban gold deposit, Xinzhou gold deposit, and Longfengchang polymetallic ore deposit, and comparisons with other mines, the authors conclude the ore-controlling implications of low-angle faults as follows. (1) Because of high temperature and high pressure, as well as strong ductile deformation, the internal energy of the elements rises in the large-scale deep ductile low-angle faults, which causes the elements to activate and differentiate from the source rocks, forming ore-bearing hydrothermal solution, and bring mineralization to happen. (2) When rising from depths and flowing along the low-angle faults, the ore-bearing hydrothermal solution will alter and replace the tectonites in the fault zone. The rocks of the hanging side and the heading side differ in lithology, texture and structure, which results in changes or dissimilarities of the physical-chemical conditions. This destroys the balance of the hydrothermal solution system and causes the dissolved ore-forming elements to precipitate; as a result, a deposit is formed. Therefore, the meso-shallow ductile-brittle low-angle faults play the role of a geochemical interface in the process of mineralization. (3) Low-angle faults are often one of the important host structures.
基金a partial result of the project“Characteristics and ore-searching indicators of the gold-bearing structure in the Qifengcha-Liulimiao area,Huairou,Beijing”,supported by the directional research fund of the former Ministry of Geology and Mineral Resources.
文摘The Qifengcha-Detiangou gold deposit is a medium-sized deposit recently found in Huairou County, Beijing. It belongs to the altered mylonite type with superimposed quartz vein type and is related to the early Yanshanian magmatic activity. Characterized by multiperiodic activity, the NE-trending Qifengcha fault is a regional ore-controlling structure in the area, and gold mineralization develops only in its southeastern part. Meanwhile, gold mineralization is controlled by the Yunmengshan metamorphic core complex. The nearly N-S- and E-W-trending low-angle detachment faults, reformed by the Qifengcha fault in the northwestern part of the core complex, are the main ore-bearing faults. All discovered gold deposits are located within an area 1.5–4.0 km away from the boundary of the upwelling centre. The N-S- (NNE-) and E-W-trending ore-bearing faults are ductile-brittle structural zones developing in shallow positions and subjected mainly to compressive deformation. The structural ore-controlling effects are as follows. (1) The attitude, shape, and distribution of gold orebodies are controlled by faults. (2) There is a negative correlation between the gold abundance and the magnetic anisotropy (P) of the altered mylonite samples from the deposit, which shows that the gold mineralization is later than the structural deformation. (3) Quartz vein type mineralization is superimposed on altered mylonite type mineralization. (4) In mineralized mylonite, the stronger the ductile shear deformation, the easier the late-stage gold mineralization to occur and the higher the gold abundance. The richest gold mineralization occurs only around the centre of the fault subjected to the strongest deformation.
基金supported by China Geological Survey (Grant No.1212010633901, 12120115024601)
文摘The Ailao Mountain is one of the most important metallogenic belts ofpolymetallic deposits in the Sanjiang region, southwestern China. Located in the southern segment of this metallogenic belt, the newly-discovered Chang＇an gold deposit is large in scale （Fig. 1A）, and has attracted much attention among geologists. The ore-hosted rocks in the district include the Late Ordovician Xiangyang Fm. sandstone and clastic rocks and the Early Silurian Kanglang Fm. dolomite. Affected by the multistage tectonic activities, stocks and dykes of lamprophyre, dolerite, syenite porphyry and orthoclasite are widely exposed, and the orebodies are in symbiosis with or crosscut the dyke rocks.
基金supported by the Funds for the programs of the National Natural Science Foundation (Noes. 41572060, U1133602)Projects of YM Lab (2011)Innovation Team of Yunnan province and KMUST (2008,2012)
文摘1 Introduction The Lehonglead-zincdeposit is a large-sized Pb-Zn depositnewly found in recent years in the Sichuan-Yunnan-Guizhou Lead-zinc Poly-metallic Mineralization Area,which occurrenceis strictly
文摘Based on quantitative and semi-quantitative mathematical and mechanical analysis of the shape, motion, structural factors, stress field and deformation field of the ore-hosting faults in the Xincheng-Hexi gold deposit, the ore-controlling features of faults and mineralization mechanism are discussed. It is concluded that the mineralization is controlled by the main faults, subsidiary fractures, joint density, mechanical features and deformation of the faults. The ore bodies are mainly located in the lower part of the convex crest and upper part of the concave trough of the main undulating fault surface. Mineralization is positively correlated to the development of subsidiary fractures and joints, which correspond to zones of low internal stress and high body strain and shear strain. They are favourable positions for mineralization and alteration.
文摘1 Introduction The Dongshengmiao deposit is a super-large Zn-Pb polymetallic sulfide deposit which occurring in the Langshan-Zhaertaaishan metallogenic belt,and located in the western margin of the North China Platform.The ore-bodies of Dongshengmiao deposits are mainly hosted in the second Formation of Langshan Group.There are some studies on the geological characteristics(Peng et al.,2004),geological and
基金supported by the Funds for the program of the National Natural Science Foundation (Noes. 41572060, U1133602)Projects of YM Lab (2011)Innovation Team of Yunnan province and KMUST (2008,2012)
文摘1 Introduction The huize Zn-Pb ore district in Yunnan province is locatedinthecentralsouthernofthe Sichuan—Yunnan—GuizhouPb-ZnPoly-metallic Mineralization Area in the southwestern margin of the Yangtze Block,and is strictly controlled by fault structures.It has developed to one of the famous production bases of lead&zinc and germanium in China.
文摘In recent2 0 years,because of the finding ofmany large- superlargegold deposits,we re- new the theories for prospecting and gain many things and conceptions.The current geo- chemical and gold- forming theories underline the importance of the early submarine volcano- sedimentation,metamorphic differention,sedimentation of terrigenous clastics,thermal spring and it’s sedimentation,syngenesis process and other hypergene supplying the source for metallogenic materials.According to the study for source bed(rock) and depsitional for- mation of gold,we find that gold will be gradually enriched and mineralized in source bed (rock) ,because of variousgeologicprocesses,such as regional metamorphism ormigmatiza- tion,geothermal bittern,volcanism. The ore- control of deep and giant fault and ductile shear beltand tectono- flash space is emphasized,especially,we should notice the long- term, succession and multistage of the
基金The Marine Science and Technology Fund of Shandong Province for Laoshan Laboratory under contract No.LSKJ202203600-2the China Ocean Mineral Resources Research and Development Association(COMRA)project under contract No.DY135-N2-1-04.
文摘Polymetallic nodules,hereinafter referred to as PN,enriched with Co,Ni,Mn,and Cu,are likely to be commercially mined in the near future.These metals in PN are potential strategic alternatives for the world’s energy transition.Therefore,intensive studies are necessary on the spatial distribution patterns of PN in the deep sea.In this study,the distribution probabilities of PN in the Pacific,Indian and Atlantic oceans were estimated based on binary logistic regression of PN occurrence with ore-controlling factors including water depth(WD),marine sediment thickness(SedTh),Calcium carbonate(CaCO_(3))concentrations in surface sediments,primary productivity(PP),near bottom current velocities(BC).Furthermore,the distribution probability of PN was constrained by seafloor ages and PN sites,and subsequently,the prospects for nodules in the Pacific,Indian and Atlantic oceans were obtained.The results indicate that the low-latitude Pacific region(30°N-30°S),particularly the Clarion-Clipperton Zone and the Penrhyn Basin,is the most promising area for PN exploration.
基金funded by the National Natural Science Foundation of China(42125203,42330809)the 111 project of the Ministry of Science and Technology(BP0719021).
文摘The Cretaceous gold deposits along the margins of the North China Craton(NCC),which formed in a craton destruction setting,display geological characteristics similar to traditional orogenic gold deposits typically associated with accretionary orogeny.These deposits,known as Jiaodong-type gold deposits,have attracted considerable attention.However,the lithospheric controls and formation mechanisms of these deposits remain unclear,as they cannot be fully explained by the supracrustal metamorphic genetic model commonly applied to classic orogenic gold deposits.In this study,the compiled S-Hg-Pb isotope ratios of gold deposits on different NCC margins display compatible variations to the Sr-Nd-Hg isotope ratios of mafic dikes spatial-temporally associated with the deposits.This implies that mantle lithosphere,metasomatized by variable proportions of oceanic and continental crust,was the source for both gold deposits and mafic dikes.Increase of oxygen fugacity and zirconεHf(t)from pre-to syn-gold granites suggests continuous basic magma underplating,which could induce concentrations of Au-rich sulfides and contribute additional Au to auriferous CO_(2)-rich fluids derived from metasomatized mantle lithosphere and basic magma.Localization of gold deposits was controlled by craton-margin sinistral shearing induced by clockwise rotation of the craton coincident with distal emplacement of metamorphic core complexes.Thus,the Cretaceous Jiaodong-type orogenic gold deposits were derived from fertilized mantle lithosphere through such crust-mantle processes within a lithosphere thinning background.
基金supported by the National Natural Science Foundation of China(Grant Nos.42130801,41230311,42125203)the 111 Project of the Ministry of Science and Technology(Grant No.BP0719021).
文摘Gold deposits in Jiaodong,termed Jiaodong-type,are tectonically located in the southeastern margin of the North China Craton.Their major features are reviewed in this paper to highlight the differences between Jiaodong deposits and other genetic types of gold deposits.The mineralization was synchronized with asthenosphere upwelling indicated by synore OIB-like mafic dike and large-scale crustal thinning suggested by decrease of Sr/Y from pre-ore to syn-ore granites.Asthenosphere upwelling induced by the roll-back of Paleo-Pacific Plate drove partial melting of lithospheric mantle and devolatilization,which induced the release of the ore-forming fluids.In concomitant with magmatic records,mineralization migrated from the western Jiaobei terrane(133–127 Ma)to the eastern Sulu orogenic belt(114–108 Ma),corresponding to the eastward roll-back of Paleo-Pacific Plate.Gold mineralization in Jiaodong formed in the transitions of ductile to brittle deformation,rapid to slow crustal uplift,and regional compression to extension.In the regional-scale,the gold deposits in the Jiaobei terrane are mostly situated at intersections between NE-trending faults and EW-trending basement faults,and gold orebodies dominantly controlled by the lithologic contacts between Precambrian metamorphic rocks and Mesozoic granites.The mineralization was dominated by the disseminated-veinlet ores related to quartz–sericite alteration in strong cataclasite-breccia zone,with subsidiary thick quartz-sulfide veins developed in secondary fault zones.The ore-forming fluids belong to a H_(2)O–CO_(2)–NaCl±CH_(4)system and show minor variations in salinity among different types of ore.Structure-fluid feedback involving fluid-rock reaction and hydrofracturing triggered the fluid phase separation and resultant gold deposition.The Jiaodong gold deposits are distinct from orogenic and intrusion-related gold deposits in terms of tectonic setting,origin of ore-forming fluids,and mechanism of gold deposition.
基金financially supported by "Key Laboratory of Gold Mineralization Processes and Resource Utilization Subordinated to the Ministry of Land and Resources (2013001)", "Key Laboratory of Metallogenic Geological Process and Resources Utilization in Shandong Province (2013001)""the Scientific Base Research Program of China’s Typical Metallic Ore Deposits (200911007)"
文摘The northwest of Jiaodong peninsula is characterized by its greatest gold concentration area, enormous gold reserves and limited time interval （115±5Ma） of gold mineralization in China. Studies show that the east area of north China began its mantle plume evolution since the Yanshanian movement, and the Laiyang sub-mantle plume and its surrounding mantle branches such as those in Guojiadian, Aishan and Panshidian were formed in the mineralization concentration area of northwestern Jiaodong peninsula. With the development of mantle plume →sub-mantle plume → mantle branch→ favorable expending structures, the deep-derived hydrothermal fluid moved up to the favorable places, such as brittle-ductile or ductile-brittle shearing zones, the internal and external contact zones of intrusions, dense fracturing zones and the contact zones between dikes and countryrocks, and concentrated into deposits. Then the gold mineralization concentration zones that are centralized on mantle branches were formed. This study takes Guojiadian mantle branch as an example to discuss their metallogenetism and conclude the metallogenetic mode.
基金the National Key Research and Development Program(No.2016YFC0600105)the National Natural Science Foundation of China(No.41672094).
文摘Structural network studies could give appropriate opportunities to understanding structural/hydrothermal events,transportation of ore-forming fluids and water/rock interaction process.Four structural deformation/hydrothermal events have been identified in the Jiaojia fault zone according to microtexture and deformation of quartz and feldspars.Plagioclase experienced ductile deformation period with bended polysynthetic twin stripes(>450℃)in the early stage,followed by K-feldspar alteration period with ductile-brittle deformation and subgrain rotation recrystallization of quartz(380-450℃).Then,sericitization period occurred extensive ductile-brittle deformation(350-420℃)and extensive subgrain rotation recrystallization with a little bulging recrystallization in quartz.In the last,gold precipitation-related pyrite-sericite-quartz alteration was dominated by brittle deformation(300-380℃)and total bulging recrystallization of quartz.From the K-feldspar alteration zone and sericitization zone to pyrite-sericitequartz alteration zone,fractal dimension values of dynamically recrystallized quartz grains increase from 1.07 and 1.24 to 1.32,the calculated paleo strain rate values of dynamically recrystallized quartz range from 10^-10^.7(380℃)-10^-9.6(450℃)and 10^-9.3(350℃)-10^-8.2(420℃)to 10^-9.5(300℃)-10^-8.0(380℃),and the paleo differential stress values increase from 36.9 and 39.3,to 121.3 MPa.The increase of fractal dimension values and decrease of grain size from pyrite-sericite-quartz alteration zone and sericitization zone to K-feldspar alteration zone decreased average water/rock ratio values,which could lead to different acidity and redox conditions of ore-forming fluids and mineralization differences.Two kinds of orecontrolling fractures have been distinguished which include the gentle dip types(18°-50°)with NW(315°-355°)and SW(180°-235°)dip hosting No.Ⅰorebodies and the steep dip types(74°-90°)with NE(45°-85°)and SE(95°-165°)dip hosting No.Ⅲorebodies.These faults/fractures crosscut altered Linglong granite of footwall of the Jiaojia fault zone as rhombohedrons that promoted the connection between fractures in the K-feldspar alteration zone and fluid flow passages near the main fault face.Research results indicate No.Ⅰand No.Ⅲorebodies should be derived from the same mineralization event and belong to different orebody types in different mineralization sites under the same structural networks.
文摘The Pengshan Sn-Pb-Zn polymetallic orefield is located in the Jiujiang-Ruichang region, which is a segment of the middle-lower Yangtze River metallogenic belt. The Pengshan late Yanshanian buried pluton with granitic composition is a calc-alkaline pluton, intrusion of which is responsible for the formation of the Sn-Pb-Zn polymetallic deposit through providing thermodynamic condition and ore-forming material. The long-active basement rifts initially formed in the Jinning period and the domal structure with induced secondary order faults formed by emplacement of the pluton, such as ring-detachment fault, top-detachment fault and joint fissure, act as the passage-way for magma and ore-forming fluid and impounding structure for ore deposit. The magma to form the pluton with DI>90 is intensively differentiated. The variation of the ore-forming fluid in composition with falling in temperature caused by action of magmatic hydrothermal convection system combined with groundwater convection system attributes to mineralization of various types in the orefield. The mineralization process can be divided into six stages, i.e., greisenization, skarnization of early stage, fluorite-stanniferous silication stage, skarnization of advanced stage, quartz and cassiterite-sulfuration stage and carbonation stage. The mineral assemblages formed in different mineralization stages are different owing to temperature changing and may be overlapped in space. Malayaite is recognized from the mineral assemblage formed in the fluorite-stanniferous silication stage. The ores in the Pengshan Sn-Pb-Zn polymetallic deposit are spatially zoned with variation from As-Sn mineral assemblage of high temperature in the inner zone through Sn-Pb and Pb-Zn-Ag mineral assemblage of middle temperature in the middle zone to fluorite mineral assemblage of low temperature in the outer zone. The exchanging of Sn, Mg and Fe between biotite and hydrothermal fluid resulted from variation of physicochemical condition during evolution processes of the hydrothermal fluid and its role in mineralization are also discussed in this paper.
